A study was undertaken to determine the feasibility of conducting a randomized controlled clinical trial of lithium for the reduction and control of levadopa induced dyskinesia in Parkinson patients. The major problem area is the clinical measurement of dyskinesia and the associated lithium response. A number of quantitative measurement methods are presently being investigated for use in the proposed study. If the trial is undertaken a two period crossover design will be used with a nonparametric analysis of the data.